Braking apparatus



May 1, 1934 s. SCHNELL ET AL BRAKING APPARATUS Filed Feb. 18, 1932 Inventors STEVE SCH NELL Atty.

Patented May 1, 1934 OFFICE 1,956,629 BRAKING APPARATUS Steve Schnell, St. Louis, and Burns Dick, Ferguson, Mo., assignors to Wagner Electric Corporation, St. ware Louis, Mo.,

a corporation of Delawhich will permit elimination of the clearance.

between the roller and the fixed surfaces with which it cooperates when the shoe is in off position, whereby the noise resulting from such clearance being taken up when the shoe is applied to the drum, will be eliminated.

Other objects of our invention will become apparent from the following description taken in connection with the accompanying drawingv in which Figure 1 is a side elevation of a brake (the drum being shown in section), disclosing our improved combined anchor and radial pressure device; Figure 2 is an enlarged view of the elements of our improved device which are carried by the brake supporting plate; Figure 3 is a cross sectional view on the line 33 of Figure 1; Figure 4 is a cross sectional view on the line 4-+-4 of Figure 1, showing a preferred construction of roller; and Figure 5 is a modified roller.

Referring to the drawing in detail, 1 indicates the drum of the brake which is secured in the usual manner to the wheel of the vehicle and is enclosed on its open side by the backing plate or support 2. The brake shoe 3 comprises a Web 4 and a lining carrying flange 5 and is adapted to have its free ends expanded into engagement with the drum by suitable means, such as the hydraulic mechanism 6. The band is biased to its oil position by the usual spring '7, its off position clearance being determined by the three adjustable stops 8.

A pair of plates 9 are secured to the web 4 of the band, one on each side thereof, and are provided with coinciding cut-out recesses on the'inner edges. One of the walls 10 of each recess is inclined to a radial line drawn through the center of the recess, and the opposite wall 11 of each recess is approximately parallel to the radial line. A plate 12 is secured to the backing plate 2 and spaced therefrom by a spacer 13 in such a manner that the lower edge of the plate lies between the plates 9 on the band. The plate 12 is slightly thinner than the space between the plates 9 so as to allow slight lateral movement of the band, and the end of the plate 12 adjacent the recesses in the plates 9 is provided with a surface 14 approximately parallel with the inclined surfaces 10 on the plates 9.

Also carried by the backing plate 2 is a second plate 15, one end of which is spaced from the backing plate by the spacer 13 and pivoted thereto by means of a pin 16. The other end of the plate 15 is provided with a bolt 1'7 which extends through an elongated opening in the backing plate, the plate being spaced from the backing plate by a washer 13. 'The outer end of the bolt is provided with a nut 17' for clamping the plate 15 in any of its rotative positions. The lower edge of the pivoted end of the plate 15 is provided with a projection 19 having a curved edge surface 20 thereon which lies opposite the surfaces 11 on the plates 9 and the surface 14 on plate 12. The surface 14 on plate 12 and the curved surface 20 on the plate 15 together form a V-shaped recess which is complementary to the recesses in the plates 9.

A roller 21 provided with enlarged ends 22 lies within the space formed by the complementary recesses and is adapted to cooperate with the surfaces 10, 11, 14 and 20. The ends of the roller 22, which cooperate with the surfaces 10 and 11 are provided with fiat surfaces, whereas the surface 23 of the roller between the enlarged ends, which cooperates with the surfaces 14 and 20, is convex. The ends 22 of the roller are so spaced apart that they do not normally engage with the side surfaces of the plates 12 and 15 as can be clearly seen from Figure 4. A tension spring '24 connected to the band and the backing plate normally maintains the roller in contact with the surfaces 10 and 14.

When the brake band 3 is engaged with the drum, there will be a slight circumferential-movement of the band with the drum in the direction -of rotation, as shown by the arrow. This circumferential movement will cause the inclined surfaces 10 to cooperate with the inclined surface 14 through the roller 21 and force the band at this point radially outwardly into tighter frictional engagement with the drum and at the same time take the torque of the band. When the drum is rotating in the reverse direction and the band is engaged therewith, the surfaces 11 and 20 will cooperate through the roller to take the torque of the band. No appreciable amount of radial pressure will be applied to the band under the latter condition since the surfaces 11 and 20 are approximately parallel with the radius of the brake assembly which passes through the center of the roller. If the roller is not at all times maintained in contact with the surfaces 10, 11, 14 and 20 when the band is disengaged from the drum, there will be a clicking of the roller when the band is applied and the clearance is taken up. This clicking will be more pronounced when the drum is rotating in a reverse direction. Our adjustable plate 15, however, is so constructed that the surfaces 14 and 20 can be maintained in contact with the roller at all times when the band is disengaged. As the brake lining wears and the surfaces cooperating with the rollers also wear, it is only necessary to unloosen the bolt 17 and move the surface 20 toward the surface 14 and take up the clearance caused by the brake band being adjusted toward the drum by the adjustable stops 8. The curvature of the surface 20 is such that a tangent at the point of contactof the roller is at all times approximately parallel to the radius of the brake assembly which passes through the center of the roller.

The making of the surface of the central part of the roller convex, permits the brake band to have a slight rocking effect. or wiggle. The cylindrical portion of the drum is not always parallel with its axis due to manufacture variations, or on account of the drum being bolted tighter to the spokes on one side than on the other. The convexity of the roller and the spacing of the plates 12 and 15 laterally from the plates 9 will, therefore, allow the band to follow the eccentric action of the drum and prevent squeaks and local high pressures between the lining and the drum as well as preventing the enlarged ends of the roller 21 from digging into the plates 12 and 15.

A modified form of roller may be used i place of the one shown in Figure 4. In this form (illustrated in Figure 5) the ends 22' of the roller are of smaller diameter than the central portion which retains its convex surface. The shoulders 25 replace the shoulders formed by the enlarged end and thereby maintain the roller in its proper position.

From the foregoing description of our invention it will be seen that our improved combined anchor and radial pressure device has produced a greatly improved brake by providing means to eliminate the clearance between the roller and the cooperating surfaces, and by providing an improved roller allowing a'more uniform wear of the brake lining.

Having fully described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

1. In braking apparatus, the combination of a support, a rotatable brake member, a friction element for engagement with said member and provided witha pair of spaced apart abutment surfaces, a pair of spaced apart abutment surfaces on said support, a roller positioned to be engageable with the abutment surfaces on the support and also with those on the friction element, and means for adjusting the position of one of said abutment surfaces relative to an abutment surface on the opposite side of said roller.

2. In braking apparatus, the combination of a support, a rotatable brake member, a friction element adapted to cooperate with said member, means on said friction element forming an abutment surface, an anchor carried by said support and having an abutment surface thereon adjacent the first named surface, a roller interposed between said surfaces, means for maintaining contact between the roller and the abutment surfaces when the friction element is in oif" position, and adjustable means contacting with the roller on the side opposite the anchor when the friction element is in off position.

3. In braking apparatus, the combination of a support, a rotatable brake member, a shoe for frictional engagement therewith and provided with an abutment surface, a pair of abutment surfaces carried by said support, a roller adapted to cooperatively engage all of said surfaces, and means for adjusting the position of one of said abutment surfaces on the support relative to the other.

4. In braking apparatus, the combination of a rotatable brake member, a shoe for frictional engagement therewith and provided with an abutment surface, a fixed member having an abutment surface thereon and spaced from the first named abutment surface, a floating roller for cooperation with said surfaces when the shoe is applied to the drum in one direction of rotation thereof, and an adjustable abutment carried by the backing plate and engaging the roller on the side opposite the abutment surface of the fixed member when the shoe is in off position, said adjustable abutment forming an anchor for said shoe in the other direction of rotation of the drum. l

5. In braking apparatus, the combination of a support, a rotatable brake member, a shoe for frictional engagement therewith and provided with a V.-shaped recess, a pair of abutments carried by said support and forming a second 'V- shaped recess, and a floating roller cooperating with the sides of both recesses, one of said abutments carried by said support being adjustable.

6. In braking apparatus, the combination of a support, a rotatable brake member, a shoe for frictional engagement therewith and provided with an abutment surface, a plate carried by the support and provided with a second abutment surface, a roller cooperating with said abutment surfaces, a second plate pivoted to said support and provided with an abutment surface engaging the roller on the side opposite the abutment surface of the first named plate, and means for adjusting and clamping said second plate in proper position.

7. In braking apparatus, the combination of a support, a rotatable brake member, a shoe for frictional engagement therewith and provided with an abutment surface, an abutment surface fixed to said support, a roller cooperating with said abutment surfaces, and an adjustable plate pivoted to said support and provided with a curved surface engaging the roller on the side opposite the fixed abutment surface.

8. In braking apparatus, the combination of a support, a rotatable brake member, a shoe for frictional engagement therewith and provided with an abutment surface, an abutment surface fixed to said support, a roller cooperating with said abutment surfaces, and an adjustable plate pivoted to said support and provided with a curved surface engaging the roller on the side opposite the fixed abutment surface, the curvature of the surface being such that for any adjusted position of the plate a tangent drawn to its point of contact with the roller will be approximately parallel with a radial line passing through the center of the drum and the center of the roller.

STEVE SCHNELL. BURNS DICK. 

